作者ilovecurl (ilovecurl)
看板trans_math
标题[考古] 政大应数89微积分二
时间Fri Jun 30 00:30:37 2006
6.
In an inverse square force field 向量F= (c*向量r)/|向量r|^3,
where c is a constant and 向量r=(x*向量i)+(y*向量j)+(z*向量k),
find the work done in moving a particle along the line from (1,1,1)
to (3,3,3).
老实说我不知道这题在说什麽,想考什麽,所以无从下手
另外同年的微积分(一)
4.For A and B positive constants,define f(x)=(e^x+Ax)^(B/x)
a.compute L1 = lim f(x) and L2 = lim f(x)
x->0 x-> ∞
这个小题我算出来的答案是L1 = e^(B(1+A)) ; L2 = e^B
b.what is the largest value of A for which the equation L1=BL2 has a
solution? What are L1 and L2 in this case?
根据我第一题算出来的,可以得出e^(AB)=B A=lnB/B
令A=lnx/x,x>0 得最大值A = 1/e 而此时 B=e
亦可得L1和L2
以上这样解这题不知道对不对,请高手或是有算的人指教一下
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1F：推 pboywc:L1算错了 应该是e^AB 218.34.243.63 06/30 07:20
2F：推 pboywc:阿 抱歉 我看错了 应该没错 早上不清醒 囧 218.34.243.63 06/30 08:35